code: def step(self):
      for param in self.params:
          if getattr(param, "grad", None) is None:
              continue
          param -= self.lr * param.grad
          param.grad = None
  
imports: import typing
  from typing import Any, Iterator
  import torch
  from torch.nn import Parameter
  from fate.arch.context import Context
  from fate.arch.protocol.mpc.common.encoding import IgnoreEncodings
  from fate.arch.protocol.mpc.mpc import FixedPointEncoder
  from fate.arch.trace import auto_trace
label_desc: Use image node_id 2 for calling the SSHENeuralNetworkOptimizerSGD obj's underlying member method code with example usage: obj.step() without return types